The present invention relates to a system for identifying, controlling, and tracking tools in an environment in which the misplacing of a single tool can have serious financial, productivity, and safety consequences, and in particular a method for providing an electronic control for the use of every tool utilized in the manufacturing operation and technical service function. The invention is a tool management system in which electronically scan/read technology is used to read 2D Data Matrix symbology from tool surfaces previous considered to be unsuited for receiving scanable electronic codes.
The current systems for controlling tools does not provide for total tool accountability. Total accountability requires that every tool have a place, every tool must be in its place, and for any tool that is not in its place a trail leads to the last authorized user of the tool and the task on which it was used. And if a lost tool is found, the exact location of its origin is known. For example, using currently available tool control systems, when a tool is found on an airplane, its origin cannot be positively identified. The tool may be identical to one that is missing from a tool kit at one air force base, but nonetheless, the tool could have been left on the plane while it was at an entirely different base. To overcome this, the Air Force, the Aerospace industry, and private industry is looking for a new system that will positively track and control every tool in its system. The tracking and control system should positively link each tool to a base and squadron, along with the kit""s name, origin, and include a list of all the other components of the kit. Further, the last authorized user of the kit and the plane on which the tool was last used (Aircraft, Kit Number, Tool Number, Tool date of purchase, and variable local use information) should also be available.
Tool control is very important in the military and Aerospace industries. A tool left in the engine of an aircraft could damage the engine and perhaps the whole plane. A tool left in the engine compartment of a helicopter or on the space shuttle can have similar consequences. The danger becomes compounded during military exercises and missions when fighters returning from a mission must be refueled and rearmed within a minimum time and returned to combat. Technical Services personnel are expected to perform their tasks within predetermined time constraints so as not to delay the return of the plane to combat. The military and Aerospace Industry refer to damage caused by tools left on board military vehicles as xe2x80x9cforeign object damagexe2x80x9d or FOD/FOE. FOD/FOE Control is a high priority in the military/management issue. The Air Force uses the term TAS, which stands for xe2x80x9cTool Accountability Systemxe2x80x9d for its program to control FOD and other branches of the military and certain industries of civilian commerce use other terms for dealing with the same problem.
The manufacturers of airplanes use manual and visual methods to track every tool that is used in the course of assembling or servicing a plane. If all the tools cannot be accounted for, the plane must be searched or possibly x-rayed before it is placed in service. The importance the Air Force""s places on Tool Control is evidenced by the fact that it is a court martial offense the first time a technician leaves a tool on board an airplane without telling a Sergeant and therefore, every technician must know exactly what tools he has brought on board the airplane so he will know if any are missing.
It has become the practice to assemble tool kits with each tool kit containing the exact tools a technician would need to work on a specific air or space vehicle. For example, if an air force base has only two or three helicopters fitted for certain weapons systems, a number of tool kits will be specifically prepared for use by technicians working on those helicopters.
Currently, the tools are monitored by assembling them into a kit in which the tools are mounted on a vertical shadow board or are inserted into shadow boxes in the pockets of pallets or drawer inserts. Each shadow board shadow box, pallet or insert has, at the point of retention of a tool, the silhouette of the tool to be retained. At the bottom of each pocket, or printed on each silhouette, is the description of the tool to be retained therein and the part number. The kits are kept in a controlled environment until they are assigned to a specific technician who is responsible for returning the kit with all the tools in each of the associated pockets therefore; inventoryxe2x80x94tool in and out.
The technology is currently available to print information on any tool in a form that is readable with the human eye; however; space limitations on the surface of the tool limit the amount of information that can be visually readable. It is the practice to print the tool number on the tool using Arabic numbers and English letters, but the more detailed information about the tool such as the name of the base, the squadron number, and the kit number is rarely printed on the surface thereof.
Prior efforts to use a traditional bar scanner or computerized tracking and computer readable codes to monitor tools have not been successful for a number of reasons. Because of their functional nature, tools have surfaces, which in the past have been considered unsuitable for receiving the known methods of applying a conventional bar code of the type readable or scanable code by a computer. A linear bar code requires a flat surface and for some tools there are no flat surfaces suitable for receiving a conventional bar code. The material of which the tool is made is also functional and is generally unsuitable for receiving a conventional bar code. Prior to the present invention, there has been no suitable method for applying an electronically readable code to chrome, stainless steel, black oxide metal, coated steel, plastic, rubber, wood, or to a concave or a convex surface.
Chrome surfaces are applied to tools to protect the metal of which the tool is made from rust or other forms of deterioration. The chrome surface provides a function, which extends the useful life of the tool, but chrome is reflective and electronic codes applied to a chrome surface using existing technology are unreadable by a scanner because the scanner is unable to detect sufficient contrast between marked and unmarked portions of the surface. Black oxide surfaces are totally non-reflective and electronic codes applied to black oxide using existing technologies are also unreadable. Similarly, plastic, rubber, and wood are not suitable media for receiving readable electronic codes. It is also unsatisfactory to provide a label to be attached to the surface of a tool because there is a risk that the label itself may become detached from the tool and become a source of FOD.
It should be appreciated that a system employing an electronically readable coding is of little value to the military unless the system will operate with a very low incidence of failure. If wear of the type ordinarily suffered to the surface of a tool will render the electronic coding on the surface unreadable, the tool will not be identifiable when it is found on a plane and the system will have failed when it is needed most.
Briefly, the present invention is embodied in a method of controlling tools where a plurality of different tools are grouped together into a set and identified to perform a given task, and where each of the plurality of tools has an associated control number or identifyer. The method envisions that the tools are retained in a suitable retainer in which each of the plurality of tools has a predetermined location. The retainer may be a toolbox or a flexible bag containing a plurality of pallets with the pallets having an indentation or pocket for each of the plurality of tools. As an alternative, the tools may be maintained in a rigid vertical shadow board or in a shadow box with suitable brackets for retaining each of the tools. Regardless of the retention method, one aspect of the invention is that as much information as possible about each tool is printed at the point of retention in a manner that is understandable using the unaided eye. Specifically, a silhouette of the tool is provided at the point of retention. Where the tool is retained in a pocket, the pocket may be shaped in the silhouette of the tool, and where the tool is retained by a bracket mounted on a vertical surface, the silhouette may be printed on the underlying surface. Also, the part number or other identifyer and as much additional information as space will allow is printed on the surface of the tool so as to be readable by the human eye.
It is desirable that the coloring of the silhouette contrast sharply with the surrounding background and with the coloring of the tools to be inserted. For example, the silhouettes may be a bright yellow or bright red in color and the surrounding background black or gray. Where the pockets of a pallet are shaped into the silhouette of a tool, the bright coloring will be applied to the bottom surface of the pocket. The bright red or yellow color tells a mechanic that one of the pockets of his pallet is empty and a tool is missing.
The invention also requires that an electronically readable code of the part number of each tool be etched into the surface of the tool, and another copy of the electronically readable code be fixed at the location for retaining the tool. To carry out the invention, the method further includes the use of an appropriate scanner for reading the electronically readable codes and a computer memory for storing all the relevant information pertaining to the tools.
To avoid potential FOD problems, the electronically readable code must be etched into the surface of the tool. For the system to operate effectively, the code must be readily readable even though the surface of the tool has been scratched or otherwise marred or obstructed. The code must be readable through a layer of grease or soil that remains on a tool after a technician has attempted to clean the coded portion of the tool with his finger or a piece of cloth.
We have found that tool surfaces which have previously been considered unsuitable for receiving an electronically readable code can be prepared for receiving a laser etching of a two dimensional code, also known as data matrix symbology. A tool laser etched with data matrix symbology is readable on a tool by a scanner even though the surface is curved, the tool has been in use for a long period of time, it has become worn or damaged.
To render a chrome surface suitable for receiving a code, the surface is roughed up using an abrasive incorporating a silica or the like, after which an epoxy coating is applied to the prepared surface. Thereafter, a laser etching will bond the epoxy to the chrome where the laser beam has struck. The unbonded excess chemical is then removed, after which the portions marked by the laser will provide sufficient contrast against the underlying sand blasted chrome surface to provide sufficient contrast for a two dimensional data matrix code to be readable.
For tools having a black oxide coated surface the black oxide is sand blasted off of a portion large enough to receive a data matrix symbology after which an epoxy coating is applied prior to laser etching. In the case of wood, rubber, or plastic, a pocket is cut into the surface of the material and the pocket is filled with an epoxy suitable for receiving a laser etching. A laser is then used to etch the surface of the epoxy.
One advantage of a data matrix symbology over a conventional linear bar code is that it is more reliably readable by a scanner. A conventional linear bar code requires at least eighty-percent contrast to be readable by a scanner, whereas data matrix symbology requires only a twenty-percent contrast. The data matrix symbology will also resist loss of information due to physical damage to the surface on which the code has been applied.
The use of a data matrix symbology has many other advantages over the conventional linear bar code. By being two dimensional, a relatively small data matrix symbology can hold twenty-five to one hundred times the information of a conventional linear bar code occupying the same amount of space. The greater retention capabilities of a data matrix symbology allow a great deal of information to be applied to the surface of the tool itself. The code on the tool may identify not only the type of tool and the tool number or other identifyer, it may include any other information related to the identity of the tool. For example, it may include that the tool is the property of the US Air Force, the name of the base from which the tool came, the squadron number, and the TAS number; that is, the Tool Accountability System number. The TAS number is a nine-digit number, which identified the tool kit in which the tool belongs. The data matrix symbology also has a verifiable information field for receiving such information as the acquisition date of the tool and, if the tool requires periodic sharpening or recalibration, the date the tool was last sharpened or calibrated.
The greater storage capabilities of the data matrix symbology can be used to resist loss of information due to damage of the coded portion of the tool by providing redundant recitations of the recorded information within the same coded area. Further protection against loss of information is provided by applying the data matrix symbology at two locations on the surface of the tool.
In accordance with the method of the present invention, the code for each tool of a tool kit is applied to the associated tool, to the surface of the tool kit at the location where the tool is retained, and to a printed listing of the tools that make up the kit. Where the kit is one of many being utilized on a military facility, such as an air force base, the computer will retain a record of all of the kits and of the names and serial numbers of the technicians to whom they have been assigned. When a tool is missing from a kit the technician who made last use of the kit and the plane that was serviced will also be stored in the memory of the computer and be readily available for later use. When a tool is found in an aircraft, a simple reading of the code applied to the tool will positively identify the source of the tool, the technician who last used it, and the date it was misplaced. Similarly, if an empty pocket or retaining bracket indicates the absence of a tool, a reading of the code at the point of retention of the tool will provide complete identification of the missing tool. If the tool is not located following a search, the computerized records will continue to retain the information regarding the missing tool until it is ultimately located. This system therefore provides a closed loop for accounting for all the tools employed in a large system such as occurs at an air force base or on an aircraft carrier.